The present invention pertains to a cage in a magnetic resonance device (MRD) with a fastening/attenuating system and methods thereof.
Magnetic resonance is used in a variety of applications to analyze and image matter, including nuclear magnetic resonance (NMR) spectroscopy, electron spin resonance (ESR) spectroscopy, nuclear quadrupole resonance (NQR), and magnetic resonance imaging (MRI). The principle is that when exposed to a uniform magnetic field, the subatomic particles in an atom will align with the magnetic field. A short electromagnetic burst disturbs the alignment, producing signals from the subatomic particles. The multitude of signals can tell an investigator about the composition, structure, and location of a sample. A more uniform magnetic field will produce less noise and more precise results. In order to produce a high quality image, the magnetic field used must be extremely stable and uniform.
The use of simple permanent magnet structures, such as C-magnet and H-magnet configurations, is not enough to achieve a sufficiently uniform magnetic field. In order to achieve such uniformity, elements correcting the inhomogeneity of the magnetic field are added, according to the principle of the fields' superposition. Coils, magnetic parts, or other means of enabling correction of the principal field are added in order to obtain a homogeneous field in the zone of interest. The precise location of these contributory components is crucial.
U.S. Pat. No. 5,959,454 to Westphal et. al. discloses a magnet arrangement for an NMR tomography system, in particular for skin and surface examinations, which contains a one-sided NMR system having two ring magnets and a cylindrical magnet. Their respective locations provide a certain degree of uniformity.
U.S. Pat. No. 6,191,584 presents a permanent magnet for NMR image detection which contains a magnetic structure having a yoke and magnetic poles, so shaped as to delimit or enclose a cavity.
U.S. Pat. No. 6,946,939 discloses a packaging plate for an interlocking magnetic circuit package comprised of multiple permanent magnets.
The ability to adjust the position and attenuation of contributory magnetic fields allows for a more precise calibration of the field in the area of interest. Therefore, a cage in a magnetic resonance device with a fastening and attenuating system still meets a long-felt need.